The present invention relates to a new and improved method of, and apparatus for, opening at least two sheets of a product, especially a printed product, preferably comprising at least one asymmetrically folded sheet in which the two sheets or pages of the folded sheet are interconnected at one side thereof and one of the sheets is formed with a marginal zone or portion protruding past the margin of the other sheet at a further open side thereof.
Generally speaking, the method and apparatus of the present invention comtemplates that the product to be opened is moved relative to an opening device including an opening element and arranging the sheet with the protruding marginal zone or portion such that an open side of the sheet faces the opening element. The opening element is, then, brought into engagement with the protruding marginal zone or region in order to open the sheets.
There are already known to the art different opening methods and apparatuses in which the sheets having the protruding marginal zone or portion are lying on top of the other sheets and are lifted therefrom; see, for instance, British Patent No. 544,365 and U.S. Pat. No. 2,237,740. Above all, particularly in the case of thin products, especially in the case of products or signatures composed of only one asymmetrically folded sheet such lifting of the sheets or pages of the folded sheet presents certain problems. For example, in the apparatus disclosed in British Patent No. 544,365 a recess must be provided in the support for the products into which engages the opening element, in order to ensure that the sheets having the protruding marginal zone or portion are positively gripped and upwardly lifted or deflected even in the case of thin products.